gpg: Fix regression in option "self-sigs-only".

* g10/import.c (read_block): Make sure KEYID is availabale also on a
pending packet.

• Reported-by: Phil Pennock
• Fixes-commit: adb120e663fc5e78f714976c6e42ae233c1990b0
• Signed-off-by: Werner Koch <wk@gnupg.org>